Structural and biochemical characterization of two heme binding sites on α1-microglobulin using site directed mutagenesis and molecular simulation.

Abstract

α1-Microglobulin (A1M) is a reductase and radical scavenger involved in physiological protection against oxidative damage. These functions were previously shown to be dependent upon cysteinyl-, C34, and lysyl side-chains, K(92, 118,130). A1M binds heme and the crystal structure suggests that C34 and H123 participate in a heme binding site. We have investigated the involvement of these five residues in the interactions with heme